Soft PWM Support

[FinalFrontierPrototyping]

Hello,

I am building a quadcopter using a Raspberry PI and C#. At the moment for I2C communication between my Raspberry PI and MPU9150 (works great).

I would like to add motor control so I would need 4 PWM outputs. Does the wrapper support the Software PWM library (https://projects.drogon.net/raspberry-pi/wiringpi/software-pwm-library)?

If not, will adding this to the wrapper work:

    [DllImport("libwiringPi.so", EntryPoint = "softPwmCreate")]
    public static extern int softPwmCreate(int pin, int initialValue, int pwmRange);

    [DllImport("libwiringPi.so", EntryPoint = "softPwmWrite")]
    public static extern void softPwmWrite(int pin, int value);

It may also be a good idea to add an example of PWM usage to the test console program.

Thanks in advance and with best regards!

[danriches]

Hi,
I haven't done any work on this library for over a year. I'm not sure if your additions will work but feel free to try them out. I would suggest you use another method of generating pwm as the library that Gordon wrote uses softpwm and may cause your C# application to run slowly, but having said that it all depends on how much processing power you need from the RasPi.

I'll take a look at this on Saturday if I can, then test it out and report back. I hope you enjoy using the library as much as I did writing it!

Regards, Dan

[davidreher]

Hey,

are you making progress on this? I cannot get it up and running ... I always get

System.EntryPointNotFoundException: softPwmCreate
  at (wrapper managed-to-native) WiringPi.GPIO:softPwmCreate (int,int,int)

In softPwm.h it says:

extern int  softPwmCreate (int pin, int value, int range) ;

When I searched for the symbol, I get the following output:

nm -A libwiringPi.so | grep softPwmCreate
libwiringPi.so:         U softPwmCreate

Best,
David

[davidreher]

Since softPwm is not that complicated I tried to implement it on my own, but now I get

mono: symbol lookup error: /home/osmc/monoLedColor/libwiringPi.so: undefined symbol: softPwmStop

although I am not using softPwm at all ...

[TrevorNewsome]

Hello all,

Not sure if this is still supported, but I have install and run according to the readme but I am getting an Unhandled Exception: System.EntryPointFileNotFoundException when running the RunTest methods for all three SPITest methods. I have even tried copying all the files in the same directory as well as using adding the files in a routing path in the app.config with no success. Its rather difficult to debug as I have having to compile the code on a Windows machine and then copy the exe on the my Pi2

Any suggestions would be welcomed. Out of curiosity, why was this project never continued with? Is there a better way of doing this?

Thank you
Trev

[danriches]

Hi Trev,
It looks like you don't have Gordon's WiringPi C library installed properly or compiled as a shared object library. The project wasn't continued with as it does exactly what most need it to do. Di you have any other requirements from it?

HTH, Dan